A wide range of audio processing system exist which comprise one or more speakers and more than one microphone. In a typical portable communications device, for example, there may be a loudspeaker, e.g. for media playback, and an earpiece speaker near to where a user's ear may be expected to be in use. The device may also comprise one or more microphones located near where a user's mouth may be expected in use, as well as one or more microphones located in close proximity to the earpiece speaker to aid with noise cancellation and echo suppression. Noise cancelling headsets also comprise multiple speakers and microphones arranged in variety of form-factors, including earbuds, on-ear, over-ear, neckband, pendant, and the like.
In any device comprising a speaker and a microphone in close proximity, suppression of acoustic echo, due to feedback from the speaker to the microphone, is desirable. Conventional echo suppression techniques utilise signals derived from microphone signals to suppress acoustic echo. When microphones become occluded or otherwise affected by external conditions, conventional techniques for echo suppression become less effective.
Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each of the appended claims.